Big cleanup
Simplify maven configuration

Use maven properties rather than a specific plugin version
and additionnal settings in the parent pom
Remove redundant maven configuration
Use managed dependencies when possible
Use the same pattern as other pom files
Move marshaller and Dsn out of connection
Create the Raven class
Create a JUL handler using Raven
Create raven appenders for logback and log4j
Handle exceptions during DSN creation

An InvalidDsnException must be thrown during the DSN creation if
the DSN is considered as Invalid
Add unit tests for DSN creation
Do not thrown an exception while building the DSN

The exception should be thrown by the DSN validation that happens
later in the DSN constructor
Remove Java7 specific method